This is a simple library for rolling RPG-style dice. The following formats are supported:

• Standard: xdy[[k|d][h|l]z][+/-c] - rolls and sums x y-sided dice, keeping or dropping the lowest or highest z dice and optionally adding or subtracting c. Example: 4d6kh3+4
• Fudge: xdf[+/-c] - rolls and sums x fudge dice (Dice that returns numbers between -1 and 1), and optionally adding or subtracting c. Example: 4df+4
• Versus: xdy[e|r]vt - rolls x y-sided dice, counting the number that roll t or greater.
• EotE: xc [xc ...] - rolls x dice of color c (b, blk, g, p, r, w, y) and returns the aggregate result.

Adding an e to the Versus rolls above makes dice 'explode' - Dice are rerolled and have the rolled value added to their total when they roll a y. Adding an r makes dice rolling a y add another die to the pool instead.

The usual go get github.com/justinian/dice.

The main entrypoint to the library is the dice.Roll function:

func Roll(desc string) (fmt.Stringer, error)

The desc argument takes any string that matches the formats above and rolls correctly. The result is returned as a RollResult (which is a fmt.Stringer for simple printing, but also contains different information based on the type of roll). See the individual roll styles for their result structures.